Link layers are typically designed only to forward packets to a directly connected entity. Sending a packet to an entity connected through one or more other nodes uses a routing protocol, which is a higher layer protocol than the link layer. Traditional routing protocols are designed for networks that are generally stable in nature. As such, the routing configurations do not change unless a new network reconfiguration is added or an existing network is deleted. Accordingly, in such static networks, the routing protocol does not need to implement routing updates very often.
These traditional routing protocols also have algorithms implemented to arrive at the entire network topology. Routers in the network exchange big data structures containing routing information of all known destination nodes. The routers may aggregate the routes of a group of destinations to arrive at a single route instead of having multiple routing entries. Also, in the current framework of the internet, routing is done based on the number of next hops and their reachability information based on the information received from peer routers.